stock boost trouble

[Cleaner13]

ok I just got my 87 GN

I did the spring cleaning
and a few bolt ons like 2 or 3

the vacuum tube is taken off the top of the fuel regulator (waiting for adjustable)

I have the big mouth intake on

the guy before me has the stock downpipe and a hollowed out cat

I also have in a thrasher 92 chip for stock injectors obviously

I have boost, air/fuel, knock, water temp, and oil pressure gauges hooked up

when I am driving my boost only maxes out at 11psi and everyone told me stock is 15, now my car moves pretty fast, but it feels like it should be faster

what do I do just to get it to the stock 15psi boost?

Carl

 

[TurboDave]

Why have you removed the vacuum line from the top of the fuel pressure regulator ???

KEEP IT HOOKED UP!! Only unhook it when you're actually looking at your static idle fuel pressure!!!!!

1. You're loosing boost through that tube unhooked like that.

2. Your fuel pressure is no longer regulated to increase with boost with it disconnected!!! A disaster waiting to happen!!!!!

 

[Cleaner13]

oh man I didnt know that

I just got my car 4 days ago and read somewhere to take it off so this way I have more fuel pressure

that could be it

I also brought it to a auto store and a guy there had a few GNs back in the day and he showed me some vacuum tube at a Y piece that I am supposed to change tubes at because of restriction

thanks turbodave

Carl

 

[Dan Thompson]

When you get your adjustable fuel pressure regulator, hopefully you will have a fuel pressure gauge by then, the vacuum line is temporarily removed to adjust fuel pressure. Once the fuel pressure is adjusted then the line is reattached.

The other vacuum line sounds like the lines for the turbo and wastegate to the sensor on top of the passenger side (PS) valve cover. These have been available at the dealers and at most vendors for about $15.00 or $16.00.

 

[UNGN]

Originally posted by Cleaner13
oh man I didnt know that

I just got my car 4 days ago and read somewhere to take it off so this way I have more fuel pressure

that could be it

I also brought it to a auto store and a guy there had a few GNs back in the day and he showed me some vacuum tube at a Y piece that I am supposed to change tubes at because of restriction

thanks turbodave

Carl

Yeah double yikes on undoing the FP regulator hose. That is an old Mustang/F-body trick. Most of those don't apply to a T-R.

You want to make sure that "Y" hose doesn't blow off during operation. You may want to use small hose clamps or zip ties to ensure they don't come off. If the hoses blow off, your car could overboost and the results be disasterous.

If your car isn't reaching 14 psi of boost after you hook up the FP regulator properly, Check to see if the Wastegate solenoid (on the valve cover) has an open port. If a vacuum hose or plug is placed on the open barb, your car will not achieve full chip boost.

You want the "Y" in the "Y" hose to be a restriction. It is built with a .050" orifice inside that will allow additional boost to be made. If the orifice is too small (some "y"s were built with too small an orifice) these can lead to too much boost, but that doesn't appear to be your problem.

 

[Cleaner13]

I want to thank everyone
I got it up and running perfect now
and like usual you guys know your stuff and are always very helpful

thank you for taking your time out of your day to help me with some of my small problems

the gauge is reading perfect now

however my knock gauge shows the last red led at max boost

I have a 92 thrasher chip in and I am running 93 octane

so anyone know what gives?

 

[turbo buicks]

ive heard my car knock at 15 psi before especially when its hot out. dont use crappy gas either. get the most octane you can find. your car will knock @ 11 psi on 92 octane also. octane booster in a bottle only raises it a couple tenths of a point so it doesnt help much. try a xylene/93 mix. it yields about 100 octane w/a 3:1 ratio mix. 3 gallons gas to 1 gallon xylene and
2 oz Marvel Mystery Oil per every gallon of xylene. ive heard you can use tranny fluid instead of the MMO but i have not tried it yet. heck i havent tried xylene yet but i know a guy that used to do it before he got alky. it works you can ask some people on this board who run xylene. alky is better though b/c after a few tanks of the xylene you could have had a nice alky kit going. alky steam cleans the inside of your engine also. xylene will clean out your injectors. also try an engine tie down strap to avoid false knock i.e. downpipe hitting header. got mine from a friend recently for $15 and it works

 

[turbo buicks]

also dont let your car knock unless you want to be blowing stuff up and replacing expensive parts. guages arent always totally accurate. i saw a board member recently tested 2 VDO guages and one was off by +1.5 lbs and the other by +1.75 lbs. you may be running more boost than you think. just cause the car ran 15 psi back in 87 when stock doesnt mean that it can do that today safely. things go bad or wear out like injectors and crap and can cause lean situation or something. the stock plenum doesnt do a very good job of evenly distributing air to all the cylinders and that causes the back 2 cylinders to run lean and knock and your engine is only as strong as the weakest cylinder, or so ive heard. a RJC power plate can even airflow to all the cylinders. they are available from www.rjcracing.com and are $59. ive heard people getting 2 lbs more boost from them so i might look into getting one. i know i want one. one more thing im sure evryone will tell you GET A SCANMASTER OR SOME KIND OF TUNING TOOL (im such a hypocrite) you cant tune these cars w/o one and you risk serious damage running modded w/o one b/c you dont kow whats going on inside the engine.